Alloy suitable for use as bearing metals



Patented Au 20, 1940 I i 2,212,178

UNITED STATES PATENT OFFICE Paul Kemp, Vienna, Germany No Drawing.Application July 21, 1938, Serial No. 220,562. Austria July 21, 1937 3Claims. (Cl. 75-166) This invention relates to alloys suitable for As aresult of these investigations it was found use as bearing metals. thatalloys, which showed only slight difie'rences The suitability of alloysas bearing metals is in in e d g S e g and compressibility. generaldetermined by investigation of a series easionally v e y eensiderabiy intheir P of properties which have been recognised to be S OI St ength a dt a alloys a g a high 5 essential. Essential requirements are a sum-Percussion strength are best adapted r ciently high resistance tocompression to ensure s pose to percussion p the alloys withstanding theoccasionally high r n s carried ut y t a y w d surface pressures, acertain hardness, to ensure that in Order to Obtain SliflieiehtDereuSSiQh 0 suflicient resistance being offered to the squeezingStrength in alleys of the three Component System 10 out of the metalfrom the bearing, and also suffia nyn t antimony content oient upsettingand transverse strength which gether wi h a of the ts arsenic a ddserves as a standard for the tenacity of the alloy, m um advantageouslyad i dening conthis last property being of very great importancstituents, must not exceed the tin content and particularly in the casevof strong impact stresses. that the lead content must amount to at least15 In addition thereto, the sliding properties, capai bility of beingsatisfactorily cast and economic on the other h it has in general beenfound c nsiderations play a corresponding part, to be advisable, inorder to obtain as favourable In view of the foregoing, the establishedfact hardness and strength s possible, that h qu that alloys, which withregard to all the above iny 0f antimony in the alloy together With 20dicated properties fulfil the conditions required quantity of thearsenic Cadmium Should of satisfactory bearing metals and hi 1 not besubstantially less than the quantity of tin showed no appreciabledifferences from-one anpreseht- Aeel'itent of C p 1 t0 has no other,behave quite differently in operation, was influence 0n the PercussionStrength of these surprising; Aboveall it was observed that in alleys-The composition of these alloys P 25 bearings, which are exposed toimpacts, some of tieuleily p d s hearing met st acthese alloys developedcracks and in part also cordihgly be maintained approximately W tcrumbled out, whilst others completely withstood the feliewing limits:

the stresses.

. According to this invention, it has been found g g fgjg 94% 30 that anadequately high bending strength together with a certain compressibilityare not arsenic plus sufficient indications of the suitability of analloy cadmium 104,7 preferably 94% f whih for bearings exposed toimpacts. In actual fact of whichAs=14 5% also in the investigation ofthese two properties of which the procedures taking place inpracticaloperation are only very incompletely represented, since, If desired, upto 2%, preferably only up to 1.5% of whilst the impacts and percussionsoccur suddencopper in addition. ly in the bearing, the determination ofthe bend- Y a t the proportions of the components 40 ing strength andcompressibility requiresaperiod n the above indicated limits, thehardness of 40 of a few minutes. the alloy can be extensivelyinfluenced. The i The working conditions are much better reprelower thecontent of tin and accordingly also the sented in the percussion test.There are no nt s f S AS a the lewet is the hardstandards for carryingout this test for bearing ness of e a y- I the ease of arsenic additionmetals and, since it was only a question of comup to 1% and in the caseof cadmium addition up 45 parative tests and not of the determination ofto about 1.5% ar Suitable, but the 811!!! Of these absolute values, theapplicants investigations two additional metals must not exceed 2%.since weretherefore carried out with an arbitrarily seno particularadvantages are obtained thereby. V lected drop hammer, in such a waythat'the latter Bearing metals of t Same y System h in 'was allowed tofall from the same height and at a low content of copper have alreadybeen pro 50 equal intervals of time onto a rod supported at posed, p t yin the pp a t's Austrian two positions. The number of impacts requiredPatents Nos. 130,903 and 135,895 ant. U. S. A. for breaking the rod wastaken as the value of Patent No. 1,754,364. The alloys 'according to theresistance to percussion or percussion these patents, however, differconsiderably from Y strength. the alloys according to this invention intheir 8% of Sn,10%- of Sb, 1.5% Of very much ;lower lead content, whilston the other hand their content of antimony plus arsenic plus cadmiumexceeds the upper limit according to this invention. I v A' comparisonof .the six-component system alloy (1) indicated in Austrian Patent No.130,-

.9 03 as optimum and having the composition: 10.4% of Sn, 9.8% 0f Sb,1.45% Of C11, 1.5% Of,

Cd, 1.2% of As and 75.65% of Pb, with an alloy (11) according to thepresent invention, for e'xv ample: 9% of,Sn, 7% of Sb, 1.3% of Cu, 1% ofCd, 0.7% of As and 81% of Pb shows that the former under the sametesting conditions breaks after three impacts whilst the latter onlybreaks alter 15 impacts. I with regard, to the resistance to compressionandbending strength, no appreciable difierences exist between the twoalloys, the latter alloy being merely somewhat softer This lower'hardness is however, not the cause of the higher per cussion strength,"since for example alloy .(III), Cu, 0% of Cd, 1% of As and 78.5% 01 Pb,which possesses the same hardness as the above alloy (11)] likewisebreaks after only three impacts.

It must be assumed that the better properties oi the all ys according tothe present invention,

. are 0cc free lead in the texture. In alloys having a lower.

oned inter alla by small quantities of so lead content, lead cannotoccur as a constituent \of the texture, since it is entirely used up forthe iormation of the" ternary Pb-Sb-Sn-Eutectic.

Moreover, the known bearing metals of this system all contain asubstantially higher quantity of antimony, 'which gives rise to theformation of more brittle crystals. The alloys according to the presentinvention are free from all the disadvantages of these known alloys.Moreover, owing to their higher lead content, they have the economicadvantage of lower cost.

What I claim is: 1..A bearing alloy characterized by a high resistanceto-impact stresses consisting of 80% to 86% of lead, 10% to 6% of tin,up to 2% 0t copper and 10% to 6% of antimony and at least one of themetals cadmium and arsenic, the amount of arsenic being at most-1%, theamount of cadmium beingat most 1.5%,.and the quantity of arsenic andcadmium together being at most 2%. Y

2. A hearing alloy characterized by a high resistance to impact stressesconsisting of about 7,% to 9% of tin, 6% to 7% of antimony, 0.5% to 1.0%of arsenic,- 0.7% to 1.0% of cadmium, up to 1.5% of copper and theremainder lead.

3. A bearing alloy characterized by a' high resistance to impactstresses consisting of 81% 'of lead, 9% oi! tin, 7% of antimony, 0.7% of1.3% of copper.

arsenic, 1% of cadmium and. i PAUL KEMP.

